Energy-Resolving Photon Counting detectors for Spectral CT make use of direct converting sensor materials, e.g. CdTe or CZT. These sensor materials are semiconductor compounds which require a high voltage bias (e.g. 300 V/mm) to ensure a homogeneous electric field within the bulk. As in conventional CT, Spectral CT detectors will require providing large coverage. To this end, Spectral CT detectors must also be tile-able on all sides, ultimately allowing extending the detector area to any desirable size.
Making a Spectral CT detector unit four side tile-able does not resolve alone all issues impacting the capability to extend the detector area. Contrary to the case of conventional detectors, the top side of the detector also requires biasing, i.e. a bias voltage must be applied to every tile or detector unit. For a limited coverage detector the high voltage may be brought for example onto the cathode by a small cable through a decoupling capacitor. For large detectors however, distributing the high voltage cannot be done with cable solutions since it typically requires soldering (i.e. impacts serviceability) and will interfere with the impinging X-ray spectrum.
US2001/035497 A1 discloses a radiation detector with a semiconducting detection component with electrodes on each side that is connected to a readout electronic circuit placed on a platform. US2008/175347 A1 discloses a direct conversion radiation detector with an anti-scatter assembly.